Receiving apparatus and receiving method

Abstract

A receiving apparatus is provided, which includes: a photoelectric detector (PD), adapted to generate current signals according to optical signals projected on the PD and digitally modulated at a high or low rate; a first switch, adapted to switch to output the high-rate or low-rate current signals; a first transimpedance amplifier (TIA), adapted to amplify the high-rate current signals into high-rate voltage signals; and a second TIA, adapted to amplify the received low-rate current signals into low-rate voltage signals. Therefore, in the present invention, high-rate and low-rate receiving paths are completely separated. This provides signals with good quality and avoids signal deterioration; and switching between the high-rate and low-rate receiving paths simplifies the structure and lowers costs.

1. A receiving apparatus, comprising:
 a photoelectric detector (PD), configured to generate high-rate or low-rate current signals according to optical signals projected on the PD and digitally modulated at a high or low rate; 
 a first switch, connected to the PD, and configured to switch to output the high-rate or low-rate current signals, and output the high-rate current signals to a first transimpedance amplifier (TIA) or output the low-rate current signals to a second TIA; 
 the first TIA, configured to amplify the received high-rate current signals into high-rate voltage signals; 
 the second TIA, configured to amplify the received low-rate current signals into low-rate voltage signals; 
 a first filter, connected to the first TIA, and configured to filter out noises of the high-rate voltage signals and reduce a noise bandwidth; 
 a second filter, connected to the second TIA, and configured to filter out noises of the low-rate voltage signals and reduce a noise bandwidth; 
 a first limiting amplifier (LA), configured to perform a limiting amplification on the filtered high-rate voltage signals; and 
 a second LA, configured to perform a limiting amplification on the filtered low-rate voltage signals; 
 a first rate detector, disposed between the first LA and the first CDR circuit, and configured to detect the limited digital voltage signals, and control the first switch to connect to the second TIA if the voltage signals are the low-rate voltage signals; and 
 a second rate detector, disposed between the second LA and the second CDR circuit, and configured to detect the limited digital voltage signals, and control the first switch to connect to the first TIA if the voltage signals are the high-rate voltage signals. 
 
     
     
       2. The receiving apparatus according to  claim 1 , wherein the first switch is controlled by a media access control (MAC) layer to switch to output the high-rate or low-rate current signals. 
     
     
       3. The receiving apparatus according to  claim 1 , further comprising:
 a first clock and data recovery (CDR) circuit, adapted to extract clocks from the limited high-rate voltage signals and recover data; and 
 a second CDR circuit, adapted to extract clocks from the limited low-rate voltage signals and recover data. 
 
     
     
       4. A passive optical network system, comprising:
 a transmitting apparatus, configured to send optical signals to a receiving apparatus; and 
 a receiving apparatus, according to  claim 3 . 
 
     
     
       5. A passive optical network system, comprising:
 a transmitting apparatus, configured to send optical signals to a receiving apparatus; and 
 a receiving apparatus, according to  claim 1 . 
 
     
     
       6. The receiving apparatus according to  claim 1 , further comprising:
 a first CDR circuit, configured to extract clocks from the high-rate voltage signals passing through the first rate detector and recover data; and 
 a second CDR circuit, configured to extract clocks from the low-rate voltage signals passing through the second rate detector and recover data. 
 
     
     
       7. A passive optical network system, comprising:
 a transmitting apparatus, configured to send optical signals to a receiving apparatus; and 
 a receiving apparatus, according to  claim 6 . 
 
     
     
       8. The receiving apparatus according to  claim 1 , further comprising:
 a second switch, configured to switch to output the filtered high-rate or low-rate voltage signals. 
 
     
     
       9. A passive optical network system, comprising:
 a transmitting apparatus, configured to send optical signals to a receiving apparatus; and 
 a receiving apparatus, according to  claim 8 . 
 
     
     
       10. The receiving apparatus according to  claim 8 , further comprising:
 a third LA, disposed after the second switch, and configured to perform a limiting amplification on the filtered high-rate or low-rate voltage signals. 
 
     
     
       11. A passive optical network system, comprising:
 a transmitting apparatus, configured to send optical signals to a receiving apparatus; and 
 a receiving apparatus, according to  claim 10 . 
 
     
     
       12. The receiving apparatus according to  claim 8 , wherein the first switch is controlled by an MAC layer to switch to output the high-rate or low-rate current signals, and the second switch is controlled by the MAC layer to switch to output the filtered high-rate or low-rate voltage signals. 
     
     
       13. A passive optical network system, comprising:
 a transmitting apparatus, configured to send optical signals to a receiving apparatus; and 
 a receiving apparatus, according to  claim 12 . 
 
     
     
       14. The receiving apparatus according to  claim 10 , further comprising:
 a third rate detector, configured to detect the limited voltage signals, control the first switch to connect to the first TIA and control the second switch to connect to the first filter if the voltage signals are the high-rate voltage signals, and control the first switch to connect to the second TIA and control the second switch to connect to the second filter if the voltage signals are the low-rate voltage signals. 
 
     
     
       15. A passive optical network system, comprising:
 a transmitting apparatus, configured to send optical signals to a receiving apparatus; and 
 a receiving apparatus, according to  claim 14 . 
 
     
     
       16. A receiving method, comprising:
 generating high-rate or low-rate current signals according to optical signals projected and digitally modulated at a high or low rate; 
 switching to output the high-rate or low-rate current signals; and 
 amplifying the high-rate current signals into high-rate voltage signals and amplifying the low-rate current signals into low-rate voltage signals; 
 filtering out noises of the high-rate or low-rate voltage signals and reducing a noise bandwidth; 
 performing a limiting amplification on the filtered high-rate or low-rate voltage signals; 
 detecting the limited digital voltage signals, amplifying the low-rate current signals into the low-rate voltage signals if the voltage signals are the low-rate voltage signals, and amplifying the high-rate current signals into the high-rate voltage signals if the voltage signals are the high-rate voltage signals; and 
 extracting clocks from the detected high-rate or low-rate voltage signals, and recovering data. 
 
     
     
       17. The receiving method according to  claim 16 , further comprising:
 filtering out noises of the high-rate or low rate voltage signals, and reducing a noise bandwidth; 
 switching to output the filtered high-rate voltage signals; and 
 performing a limiting amplification on the filtered high-rate or low-rate voltage signals. 
 
     
     
       18. A passive optical network system, comprising:
 a transmitting apparatus, configured to send optical signals to a receiving apparatus; and 
 a receiving apparatus, according to  claim 2 .